<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <!-- <input type="text" value="电脑"> -->
    <input type="checkbox" name="" id="">
    <button disabled>Dianji</button>
    <script>
        //1.获取元素
        // const username = document.querySelector('input')
        //2.获取值
        // console.log(username.value);
        //3.设置表单的值
        // username.value = '手机'
        // username.type = 'password'
        // console.log(username.value);

        // 1.获取元素
        const ipt = document.querySelector('input')
        ipt.checked = 'true'

        const bt = document.querySelector('button')
        bt.disabled = false
    </script>
</body>
</html>